The present invention relates to a impact or contact sensor which is capable of differentiating between lower force impacts, such as a contact event between a pedestrian and a vehicle, and more severe contact events, such as those experienced when a vehicle impacts upon a traffic barrier or another vehicle.
Automotive designers have used a variable plethora of sensors for the purpose of determining whether a vehicle has impacted with a pedestrian, or an inanimate object such as a pole, a barrier or another vehicle. The sensing of low-force impacts, such as that between a vehicle and a pedestrian, or a very low velocity impact of the vehicle against a rigid object is ideally performed with a reversible type of sensor. Reversibility allows the sensor to continue in service after a low force impact event. It is known to provide linear strip type sensors for this purpose, and U.S. Pat. No. 6,744,354 discloses such a sensor. Sensors useful for sensing pedestrian impacts are not however, generally optimized for sensing more severe impacts. Thus, designers have employed two types of sensors with some vehicles. The use of more than one type of sensor, of course, entails additional expense and complexity in the sensor control system.
A sensor and sensor system according to the present invention provides for low-force impact sensing applicable to pedestrian impacts, as well as to high-force impacts against larger and smaller inanimate objects such as poles, barriers, and other vehicles.